Water heating device and method for manufacturing smoke tube for water heating device

ABSTRACT

Disclosed are a water heating device, and a method for manufacturing a smoke tube for a water heating device. The water heating device includes a body having an interior space that accommodates water, a combustion chamber provided in the interior space of the body and that provides a space for a combustion reaction, a smoke tube connected to the combustion chamber, that guides a combustion gas generated during the combustion reaction from the combustion chamber to an outside of the body, and wound in a spiral shape in at least a partial section, and a turbulator provided in at least a partial section of an interior of the smoke tube to make the combustion gas flowing in the interior of the smoke tube turbulent, and wound in a spiral shape to correspond to the spiral shape of the smoke tube.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority to Korean Patent Application No. 10-2020-0117130, filed in the Korean Intellectual Property Office on Sep. 11, 2020, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a water heating device, and a method for manufacturing a smoke tube for a water heating device.

BACKGROUND

A water heating device is a device that heats water. For example, a water heating device may include a boiler that heats a desired area by heating water in a container, and a water heater that discharges the heated water.

Among the water heating devices, a water heating device including a smoke tube in a coil form in an interior thereof is present. The water heating device uses a principle, in which gas heated by a burner heats water located in an interior space of the water heating device while passing through the smoke tube in the coil form.

Meanwhile, a turbulator may be located in the interior of the smoke tube. The turbulator may increase a heat exchange efficiency between the water and the gas located in the interior space of the water heating device by making the flows of the gas turbulent in the interior of the smoke tube.

However, the water heating device including the smoke tube in the coil form is mass-produced while a turbulator is not present in the interior thereof due to the shape of the smoke tube, and thus, the flows of the gas becomes laminar and heat exchange efficiency is lowered.

Furthermore, in the water heating device including the smoke tube in the coil form, a turbulator is not disposed in the interior thereof, and thus, a length of the smoke tube has to be larger for securing heat transfer performance, and due to this, a space in the interior, in which water is filled, may become narrower.

Furthermore, when a turbulator is to be disposed in the smoke tube in the coil form, it is difficult to dispose the turbulator in the interior of the smoke tube due to the shape of the smoke tube.

SUMMARY

The present disclosure has been made to solve the above-mentioned problems occurring in the prior art while advantages achieved by the prior art are maintained intact.

An aspect of the present disclosure provides a water heating device including a turbulator in an interior of a smoke tube.

The technical problems to be solved by the present disclosure are not limited to the aforementioned problems, and any other technical problems not mentioned herein will be clearly understood from the following description by those skilled in the art to which the present disclosure pertains.

According to an aspect of the present disclosure, a water heating device includes a body having an interior space that accommodates water, a combustion chamber provided in the interior space of the body and that provides a space for a combustion reaction, a smoke tube connected to the combustion chamber, that guides a combustion gas generated during the combustion reaction from the combustion chamber to an outside of the body, and wound in a spiral shape in at least a partial section, and a turbulator provided in at least a partial section of an interior of the smoke tube to make the combustion gas flowing in the interior of the smoke tube turbulent, and wound in a spiral shape to correspond to the spiral shape of the smoke tube.

In another embodiment, the turbulator may be a twisted turbulator.

In another embodiment, when the turbulator is divided into a plurality of parts, and it is defined that, among the plurality of parts, parts located on an upstream side with respect to a flow direction of the combustion gas are upstream parts and parts located on a downstream side of the upstream parts are downstream parts, a pitch of at least some of the upstream parts may be larger than a pitch of at least some of the downstream parts.

In another embodiment, when the turbulator is divided into a plurality of spiral areas, and it is defined that, among the plurality of spiral areas, areas located on an upstream side with respect to a point, at which condensate is generated, are upstream spiral areas, and areas located on a downstream side of the upstream spiral areas are downstream spiral areas, and it is defined that a length connecting two points having the same phase in a spiral is a helical pitch, a helical pitch of at least some of the upstream spiral areas may be smaller than a helical pitch of at least some of the downstream spiral areas.

In another embodiment, the turbulator may be provided between a specific point on the smoke tube, which is spaced apart from an inlet of the smoke tube, through which the combustion gas is introduced, by a specific distance along a flow direction of the combustion gas, and an outlet of the smoke tube, through which the combustion gas is discharged.

In another embodiment, a plurality of turbulator units for making the combustion gas turbulent may be connected to each other to form the turbulator, and physical characteristics of at least two of the plurality of turbulator units may be different.

In another embodiment, the plurality of turbulator units may be arranged according to a specific reference based on the physical characteristics.

According to an aspect of the present disclosure, a method for manufacturing a smoke tube applied to a water heating device includes preparing the smoke tube that is linear, preparing a twisted turbulator, inserting the twisted turbulator into an interior of the smoke tube, and winding the smoke tube in a spiral shape together with the twisted turbulator.

In another embodiment, the preparing of the twisted turbulator may include preparing a plurality of turbulator units, of which physical characteristics of at least two are different, and arranging and coupling the plurality of turbulator units according to a specific reference based on the physical characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present disclosure will be more apparent from the following detailed description taken in conjunction with the accompanying drawings:

FIG. 1 is a view illustrating a body and a smoke tube of a water heating device according to an embodiment of the present disclosure;

FIG. 2 is a view illustrating a combustion chamber and a smoke tube of a water heating device according to an embodiment of the present disclosure;

FIGS. 3 and 4 are views illustrating a turbulator of a water heating device according to an embodiment of the present disclosure;

FIG. 5 is a view illustrating a part of a twisted turbulator according to an example;

FIG. 6 is a flowchart illustrating a method for manufacturing a smoke tube applied to a water heating device according to an embodiment of the present disclosure; and

FIG. 7 is a flowchart illustrating an operation of preparing a twisted turbulator in FIG. 6.

DETAILED DESCRIPTION

Hereinafter, some embodiments of the present disclosure will be described in detail with reference to the exemplary drawings. In providing reference numerals to the constituent elements of the drawings, the same elements may have the same reference numerals even if they are displayed on different drawings. Further, in the following description of the present disclosure, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure rather unclear.

Configuration of Water Heating Device

A water heating device according to an embodiment of the present disclosure relates to a water heating device having an improved heat exchange efficiency. The water heating device according to the embodiment of the present disclosure may include a body 10, a combustion chamber 20, a smoke tube 30, and a turbulator 40. FIG. 1 is a view illustrating a body 10 and a smoke tube 30 of a water heating device according to an embodiment of the present disclosure. FIG. 2 is a view illustrating a combustion chamber 20 and the smoke tube 30 of a water heating device according to an embodiment of the present disclosure. FIGS. 3 and 4 are views illustrating a turbulator 40 of a water heating device according to an embodiment of the present disclosure. For reference, FIG. 2 illustrates the body 10 in a dotted line for convenience of description, and FIGS. 3 and 4 illustrate the smoke tube 30 in a dotted line for convenience of description.

The body 10 may include an interior space “S” configured to accommodate water. The combustion chamber 20 may be provided in the interior space “S” of the body 10. As illustrated in FIG. 2, the combustion chamber 20 may be located on an upper side of the interior space “S” of the body 10. However, this may be different according to a kind of the water heating device. The water heating device illustrated in FIG. 2 may be understood as a downstream type water heating device.

The combustion chamber 20 may provide a specific space for a combustion reaction. The smoke tube 30 may be connected to the combustion chamber 20, and may guide a combustion gas generated during the combustion reaction from the combustion chamber 20 to an outside of the body 10. The smoke tube 30 may be wound in a spiral shape in at least a partial section. An inlet 31 of the smoke tube 30 may be provided with a blower (not illustrated) that generates a flow of the combustion gas.

The turbulator 40 may be provided in the at least a partial section of the interior of the smoke tube 30 to make the combustion gas flowing in the interior of the smoke tube 30 turbulent.

As illustrated in FIGS. 3 and 4, the turbulator 40 may be wound in a spiral shape to correspond to the spiral shape of the smoke tube 30.

For example, a water heating device that does not include a turbulator in the interior of the smoke tube may be considered. In this case, the flow of the combustion gas in the smoke tube may be laminar so that heat exchange efficiency may deteriorate.

In the water heating device according to the embodiment of the present disclosure, because the turbulator 40 that is wound in the spiral shape to correspond to the spiral shape of the smoke tube 30 is disposed in the interior of the smoke tube 30, the combustion gas flowing in the interior of the smoke tube 30 may be made turbulent so that the heat exchanger efficiency may increase.

Furthermore, in the water heating device according to the embodiment of the present disclosure, because the turbulator 40 wound in the spiral shape to correspond to the spiral shape of the smoke tube 30 is disposed in the interior of the smoke tube 30, the heat exchange efficiency is high as compared with a case, in which there is no turbulator, and thus because a length of the smoke tube 30 may be manufactured to be small under the same heat transfer performance as compared with the case, in which there is no turbulator, more water may be contained in the interior space “S”.

Twisted Turbulator 41

The turbulator 40 may be a twisted turbulator 41. The twisted turbulator 41 may have a dual spiral shape, of which long sides of a flat plate extending in one direction are made to be symmetrical to each other by twisting the plate with respect to a specific axis that faces one direction. FIG. 5 is a view illustrating a part of a twisted turbulator according to an example. The turbulator 40 of the water heating device according to the embodiment of the present disclosure may be understood as having a shape obtained by winding the twisted turbulator of FIG. 5 in the spiral shape.

For example, a case, in which the general plate-shaped turbulator is used instead of the twisted turbulator, may be considered. In this case, it may not be easy to wind the turbulator in the spiral shape to insert the turbulator into the smoke tube in the spiral shape.

Because the water heating device according to the embodiment of the present disclosure uses the twisted turbulator, it may be easy to wind the turbulator in the spiral shape to correspond to the shape of the smoke tube of the spiral shape as compared with the plate-shaped turbulator. Accordingly, because the twisted turbulator of the spiral shape may be disposed in the interior of the smoke tube of the spiral shape, the heat exchange efficiency may be improved.

Upstream Parts 42 and Downstream Parts 43

Hereinafter, the upstream parts 42 and the downstream parts 43 will be described below with reference to FIG. 3. A pitch P1 of at least some of the upstream parts 42 of the turbulator 40 may be larger than a pitch P2 of at least some of the downstream parts 43 of the turbulator 40. A pitch “P”, as illustrated in FIGS. 3 and 5, may be understood as a length connecting two points of the same phase on the long sides of the twisted turbulator 41, which have a dual spiral shape.

The upstream parts 42 may mean, among the plurality of parts obtained by dividing the turbulator 40, parts that are located on an upstream side with respect to a flow direction “D” of the combustion gas. The downstream parts 43 may mean parts that are located on a downstream side of the upstream parts 42. For example, the turbulator 40 may be divided into the upstream parts 42 and the downstream parts 423 with respect to a point corresponding to 50% of the entire length of the turbulator 40.

In an example of another reference for dividing the turbulator 40 into the upstream parts 42 and the downstream parts 43, the turbulator 40 may be divided into the upstream parts 42 and the downstream part 43 with respect to a point, at which an increment of the pitch “P” in the entire turbulator 40 is 10% or more. Then, the pitch P1 of the at least some of the upstream parts 42 of the turbulator 40 may be larger than the pitch P2 of the at least some of the downstream parts 43 of the turbulator 40.

In more detail, a temperature of the combustion gas in a section, in which the upstream parts 42 are disposed in the smoke tube 30, may be higher than that in a section, in which the downstream parts 43 are disposed in the smoke tube 30. An aspect that the temperature of the combustion gas is high may mean that a density of the combustion gas is low. In other words, the density of the combustion gas in the section, in which the upstream parts 42 are disposed in the smoke tube 30, may be lower than that in the section, in which the downstream parts 43 are disposed in the smoke tube 30.

That is, with reference to the combustion gas of the same mass, a volume of the combustion gas in the section, in which the upstream parts 42 are disposed, is larger than that in the section, in which the downstream parts 43 are disposed.

Accordingly, the pitch P1 of the at least some of the upstream parts 42 of the turbulator 40 may be larger than the pitch P2 of the at least some of the downstream parts 43 of the turbulator 40 so that a resistance to the combustion gas of the upstream parts 42 may be reduced.

An aspect that a pitch of a specific portion of the turbulator is relatively large may mean that the number of twisting of the turbulator in the same reference length is relatively small. This may be understood that the turbulator generates less turbulence.

In the water heating device according to the embodiment of the present disclosure, because the pitch “P” of the at least some of the upstream parts 42 is larger than the pitch “P” of the at least some of the downstream parts 43, more turbulence is generated in the downstream parts 43, in which the combustion gas of a relatively low temperature is located, than in the upstream parts 42, in which the combustion gas of a relatively high temperature so that the heat exchange efficiency may be improved.

Furthermore, the turbulator 40 may be applied as a resistance to wind generated by a blower to cause the combustion gas to flow. In the water heating device according to the embodiment of the present disclosure, because the pitch “P” of the at least some of the upstream parts 42 is larger than the pitch “P” of the at least some of the downstream parts 43, strong flows with characteristics of laminar flows may be generated in the parts, in which the upstream parts 42 of the smoke tube are located, than in the parts, in which the downstream parts 43 of the smoke tube are located. Accordingly, because the resistance to the blower, which is generated by the upstream parts 42 of the turbulator, may be reduced, the load of the blower may be reduced.

In order to further decrease the above-described blower, the turbulator 40 may be provided between a specific point 33 on the smoke tube 30 and an outlet 32 of the smoke tube 30. The specific point 33 on the smoke tube 30 may mean a point that is spaced apart from the inlet 31 of the smoke tube 30 by a specific distance along the flow direction “D” of the combustion gas.

The flow direction “D”, as illustrated in FIGS. 3 and 4, may be understood as a direction, in which the combustion gas flows along the shape of the smoke tube 30. Hereinafter, the expressions of the upstream and the downstream may be described below with reference to the flow direction “D” of the combustion gas in the smoke tube 30.

For example, a material of the turbulator 40 may be variously determined. An area of the turbulator 40, which may be oxidized or corroded due to high heat may be different according to the material of the turbulator 40, the turbulator may be disposed in a section in the smoke tube 30, in which a temperature at which the turbulator 40 may be neither oxidized nor corroded, is formed.

For example, when a temperature at which steel grade x is corroded at a high temperature is 600 degrees, a temperature of the inlet 31 of the smoke tube 30 in a state, in which there is no turbulator, is 1100 degrees, and a temperature of the outlet 32 is 100 degrees, the turbulator manufactured of steel grade x may be disposed in a section from a point corresponding to 50% of the downstream side of the smoke tube 30 to the outlet 32. That is, in the case of steel grade x, the specific point may be a point of 50% corresponding to the downstream side of the smoke tube 30.

As another example, when a temperature, at which steel grade y is corroded at a high temperature, is 300 degrees, a temperature of the inlet 31 of the smoke tube 30 in a state, in which there is no turbulator, is 1100 degrees, and a temperature of the outlet 32 is 100 degrees, the turbulator manufactured of steel grade y may be disposed in a section from a point of 20% of the downstream side of the smoke tube 30 to the outlet 32. That is, in the case of steel grade y, the specific point may be a point of 20% of the downstream side of the smoke tube 30.

In this case, because the turbulator 40 may be disposed in a section of the smoke tube 30, in which a temperature at which the turbulator 40 may be neither oxidized nor corroded is formed, the oxidation or corrosion of the turbulator 40 may be reduced.

Furthermore, in this case, because the turbulator 40 is not disposed at a location from the inlet 31 to the specific point 33, a load of the blower may be further reduced.

Upstream Spiral Areas 44 and Downstream Spiral Areas 45

Hereinafter, the upstream spiral areas 44 and the downstream spiral areas 45 of the turbulator 40 will be described below with reference to FIG. 4. A helical pitch HP1 of at least some of the upstream spiral areas 44 of the turbulator 40 may be small as compared with a helical pitch HP2 of at least some of the downstream spiral areas 45.

The upstream spiral areas 44 may mean, among a plurality of spiral shape areas, areas that are located on an upstream side with respect to a point, at which the condensate is generated, after the turbulator 40 is divided into the areas having a plurality of spiral shapes. The downstream spiral areas 45 may mean areas that are located on the downstream side of the upstream spiral areas 44.

For example, because the point, at which the condensate is generated relatively, may be formed on the upstream side of the smoke tube 30 when a temperature of the water filled in the interior space “S” of the body 1 is relatively low, it may be understood that the lengths of the downstream spiral areas are relatively large.

In contrast, because the point, at which the condensate is generated relatively, may be formed on the downstream side of the smoke tube 30 when a temperature of the water filled in the interior space “S” of the body 1 is relatively high it may be understood that the lengths of the downstream spiral areas are relatively small.

As an example of another reference for dividing the upstream spiral areas 44 and the downstream spiral areas 45, the turbulator 40 may be divided into the upstream spiral areas 44 and the downstream spiral areas 45 with respect to a point corresponding to 50% of the entire length of the turbulator 40.

As another example, the turbulator 40 may be divided into the upstream spiral areas 44 and the downstream spiral areas 45 with respect to a portion, at which a thickness of the turbulator 40 is changed.

As another example, the turbulator 40 may be divided into the upstream spiral areas 44 and the downstream spiral areas 45 with respect to a portion, at which a steel grade of the turbulator 40 is changed.

As another example, the turbulator 40 may be divided into the upstream spiral areas 44 and the downstream spiral areas 45 with respect to a portion, at which an increment of the helical pitch HP is 10% or more. Hereinafter, the helical pitch HP will be described below.

The helical pitch HP, as illustrated in FIG. 4, may mean a length connecting the two points having the same phase in the spiral. That is, it may be understood that an inclination drawn by a locus of a point that is moved along a spiral is gentle at a portion of a spiral having a small helical pitch as compared with a portion having the spiral having a large helical pitch.

Because the temperature of the combustion gas at a portion of the smoke tube 30, which is located on the downstream side, is relatively low, more condensate may be generated at a portion of the smoke tube 30, which is located on the upstream side, as compared with a portion of the smoke tube 30, which is located on the downstream side. The heat exchanger according to the embodiment of the present disclosure may be advantageous in discharging the condensate because an inclination of an area of the smoke tube 30, which is located on the downstream side, may be large to correspond to the at least some of the downstream spiral areas 45 as the helical pitch HP1 of the at least some of the upstream spiral areas 44 is smaller than the helical pitch HP2 of the at least some of the downstream spiral areas 45.

As an example, when an inclination of the downstream spiral areas 45 is 3° or less, the condensate gathers without being discharged due to a surface tension when the condensate is generated, and thus a durability of the smoke tube 30 is problematic, for example, the smoke tube 30 is corroded. Accordingly, at least some of the downstream spiral areas 45 may have a helical pitch, by which an inclination of the downstream spiral areas 45 may become 3° or less.

Turbulator Unit 40′

The turbulator 40 may be formed by connecting the plurality of turbulator units 40′ for making the combustion gas turbulent. The physical characteristics of at least two of the plurality of turbulator units 40′ may be different. The physical characteristics, for example, may include all of an external appearance, a material, a length, a thickness, a mass, a volume, a strength, a density, a pitch “P” (FIG. 5), and the like.

For example, because a temperature in the upstream area of the smoke tube 30 is higher than a temperature in the downstream side of the smoke tube 30, the turbulator 40 may be oxidized or corroded. A thickness of the turbulator discharged in the upstream area of the smoke tube may be larger than a thickness of the turbulator discharged in the downstream area of the smoke tube. Furthermore, a heat-resistant performance of the turbulator discharged in the upstream area of the smoke tube may be better than a heat-resistant performance of the turbulator discharged in the downstream area of the smoke tube.

The plurality of turbulator units 40′ may be arranged according to a specific reference based on the physical characteristics. For example, the turbulator units having a large pitch may be disposed relatively on the upstream side, and the turbulator units having a small pitch may be arranged relatively on the downstream side. Furthermore, the turbulator units having a large mass may be disposed relatively on the upstream side, and the turbulator units having a small mass may be disposed relatively on the downstream side.

Because the physical characteristics of the at least two of the plurality of turbulator units are different, a turbulator having a desired shape may be manufactured according to a need of the user. For example, when the user desired to dispose the turbulator units having the large pitch on the upstream side of the smoke tube 30 and dispose the turbulator units having the small pitch on the downstream side of the smoke tube 30, the turbulator having the shape may be manufactured.

Method for Manufacturing Smoke Tube

Hereinafter, a method for manufacturing a smoke tube applied to a water heating device according to an embodiment of the present disclosure will be described with reference to FIGS. 6 and 7. FIG. 6 is a flowchart illustrating a method for manufacturing a smoke tube applied to a water heating device according to an embodiment of the present disclosure. FIG. 7 is a flowchart illustrating an operation of preparing a twisted turbulator in FIG. 6.

A general configuration of the water heating device is as described above, and thus a detailed description thereof will be omitted. Furthermore, FIGS. 1 to 5 may be referenced for understanding.

The method for manufacturing the smoke tube 30 applied to the water heating device, as illustrated in FIG. 6, may include an operation (S100) of preparing a linear smoke tube, an operation (S200) of preparing a twisted turbulator, an operation (S300) of inserting the twisted turbulator into the smoke tube, and an operation (S400) of winding the smoke tube in a spiral shape together with the twisted turbulator.

For example, a method of inserting the linear twisted turbulator after the linear smoke tube is prepared and is wound in the spiral shape may be considered. In this case, it may be difficult to insert the linear twisted turbulator due to the spiral shape of the smoke tube.

According to the method for manufacturing the smoke tube applied to the water heating device according to the embodiment of the present disclosure, because the smoke tube and the twisted turbulator are wound in the spiral shapes together after the twisted turbulator is inserted into the linear smoke tube, the smoke tube, in which the twisted turbulator is disposed, may be efficiently manufactured.

As illustrated in FIG. 7, the operation of preparing the twisted turbulator may include an operation (S210) of preparing a plurality of turbulator units, of which physical characteristics of at least two are different, and an operation (S220) of arranging and coupling the plurality of turbulator units according to a specific reference based on physical characteristics thereof.

For example, the user desires to prepare a twisted turbulator, in which the turbulator units having a relatively large pitch are disposed on the upstream side of the smoke tube and the turbulator units having a relatively small pitch are disposed on the downstream side of the smoke tube, a plurality of turbulator units having the relatively large pitch and a plurality of turbulator units having the relatively small pitch are prepared and then may be arranged and connected to each other depending on the lengths of the pitches.

According to the present disclosure, because the turbulator that may make flows turbulent is disposed in the interior of the spiral smoke tube, heat exchange efficiency may be increased.

Furthermore, according to the present disclosure, because the turbulator may be effectively disposed in the interior of the spiral smoke tube, work efficiency may be increased.

The above description is a simple exemplification of the technical spirits of the present disclosure, and the present disclosure may be variously corrected and modified by those skilled in the art to which the present disclosure pertains without departing from the essential features of the present disclosure. Accordingly, the embodiments disclosed in the present disclosure is not provided to limit the technical spirits of the present disclosure but provided to describe the present disclosure, and the scope of the technical spirits of the present disclosure is not limited by the embodiments. Accordingly, the technical scope of the present disclosure should be construed by the attached claims, and all the technical spirits within the equivalent ranges fall within the scope of the present disclosure. 

What is claimed is:
 1. A water heating device comprising: a body having an interior space configured to accommodate water; a combustion chamber provided in the interior space of the body and configured to provide a space for a combustion reaction; a smoke tube connected to the combustion chamber, configured to guide a combustion gas generated during the combustion reaction from the combustion chamber to an outside of the body, and wound in a spiral shape in at least a partial section; and a turbulator provided in at least a partial section of an interior of the smoke tube to make the combustion gas flowing in the interior of the smoke tube turbulent, and wound in a spiral shape to correspond to the spiral shape of the smoke tube.
 2. The water heating device of claim 1, wherein the turbulator is a twisted turbulator.
 3. The water heating device of claim 2, wherein when the turbulator is divided into a plurality of parts, and it is defined that, among the plurality of parts, parts located on an upstream side with respect to a flow direction of the combustion gas are upstream parts and parts located on a downstream side of the upstream parts are downstream parts, a pitch of at least some of the upstream parts are larger than a pitch of at least some of the downstream parts.
 4. The water heating device of claim 2, wherein when the turbulator is divided into a plurality of spiral areas, and it is defined that, among the plurality of spiral areas, areas located on an upstream side with respect to a point, at which condensate is generated, are upstream spiral areas, and areas located on a downstream side of the upstream spiral areas are downstream spiral areas, and it is defined that a length connecting two points having the same phase in a spiral is a helical pitch, a helical pitch of at least some of the upstream spiral areas are smaller than a helical pitch of at least some of the downstream spiral areas.
 5. The water heating device of claim 1, wherein the turbulator is provided between a specific point on the smoke tube, which is spaced apart from an inlet of the smoke tube, through which the combustion gas is introduced, by a specific distance along a flow direction of the combustion gas, and an outlet of the smoke tube, through which the combustion gas is discharged.
 6. The water heating device of claim 1, wherein a plurality of turbulator units for making the combustion gas turbulent are connected to each other to form the turbulator, and wherein physical characteristics of at least two of the plurality of turbulator units are different.
 7. The water heating device of claim 6, wherein the plurality of turbulator units are arranged according to a specific reference based on the physical characteristics.
 8. A method for manufacturing a smoke tube applied to a water heating device, the method comprising: preparing the smoke tube that is linear; preparing a twisted turbulator; inserting the twisted turbulator into an interior of the smoke tube; and winding the smoke tube in a spiral shape together with the twisted turbulator.
 9. The method of claim 8, wherein the preparing of the twisted turbulator includes: preparing a plurality of turbulator units, of which physical characteristics of at least two are different; and arranging and coupling the plurality of turbulator units according to a specific reference based on the physical characteristics. 